Order not preserved when shuffling config provider seed hosts

In DefaultConfigProvider.seedHosts we shuffle the list of network addresses, but then we put them back into a HashSet which does not respect insertion order. In fact, the iteration order is often the same after shuffling and inserting into the new HashSet as it was in the original Set.

When shuffling, we should use a LinkedHashSet so that when iterating, items are returned in the shuffled order.